Drilling apparatus



Aug. 19, 1969 RACHELIS ETAL. 3,451,750

- DRILLING APPARATUS Filed Feb. 10, 1967 3 Sheets-Sheet l FIG.|

Aug. 19, 1969 F. ACHE LIS ETAL 3,461,750

DRILLING APPARATUS Filed Feb. 10, 1967 3 Sheets-Sheet 2 r 54a. 48 U T s7874 32 64 3,36) Ma as 148 5 .42 I 42 12 (i) 44 I 44 38 f INVENTOR 2s 5ig Y 5 B R8$I P J 38 34 24 ROGER MSHIERHAN WILLIAM H ems ATTORNEYSUnited States Patent 3,461,750 DRILLING APPARATUS Frederic Achelis, PaloAlto, Roy J. Brown, Los Gatos, and Roger M. Sherman and William M. Bibb,Palo Alto, Calif., assiguors to The Kor-it Company, Inc., Santa Clara,Calif.

Filed Feb. 10, 1967, Ser. No. 615,127 Int. Cl. B23b 41/08, 45/14 US. Cl.77-14 Claims ABSTRACT OF THE DISCLOSURE Drilling apparatus suitable fordrilling holes in tile, concrete or metallic structures, such as sewerpipe. The drill bit support can be held either by flexible connectingmembers or by a vacuum device to the workpiece to be drilled and thedrill bit can be disposed at a right angle to the workpiece or inclinedrelative thereto. Pipe of substantially any diameter and flat surfacescan be drilled with the apparatus.

This invention relates to improvements in the drilling of rigid orrelatively rigid structures and, more particularly, to drillingapparatus for drilling holes in tile, concrete or other pipes.

The present invention is especially adapted for the tapping of sewermains to make house-to-sewer service connections. In the past, a numberof methods have been employed to effect such connections. When sewermains are initially laid, it is oftentimes the practice to provide forhouse service connections by predetermining the location ofhouse-to-sewer lines to be laid in the future and installing stopperedYs or Ts along the main sewer line. A location record is kept so thatthe Ys or Ts can be found when house service connections are made. Thispractice is unsatisfactory because, in many cases, the Ys or Ts becomebroken or cracked loose from the sewer line due to heaving of the earth.Moreover, these components are expensive, are difficult to store andship, and are structurally weak where they are joined with sewer mains.

Sewer mains have also been tapped by the use of hand tools such aschisels, picks, and the like. Extreme care must be used in forming holesin this manner because sewer tiles are generally quite brittle andconcrete pipe is quite easily cracked. It is very difficult to get evena semblance of a round hole in such pipes with hand tools. Thus, a goodfit for the connecting Y or T'is not easily achieved. The disadvantagesof this method are that the sewer main is oftentimes weakened, cuttingtime is quite long, and the irregularity of the hole size required aconsiderable amount of sealing compound at the joint, thus furtherdetracting from the strength of the joints.

Still another method of tapping a sewer line is by the insertion of Tsor Ys in existing sewer lines, but this requires that the flow of thesewage in the line be interrupted during the installation, such as bypumping around the line. Techniques of this type are sometimes known inthe trade as buckle-in, sisson coupling, and rollin methods. Theinsertion of a Y or T is not satisfactory because of flow interruptionand structural weakening of the sewer line itself.

The drilling of holes in sewer mains is not new, but the apparatus thathas been employed in the past to do this has several limitations. One ofthese limitations is that conventional apparatus can be usedconveniently and with a minimum of difliculty only with a pipe having arelatively small maximum diameter. Such apparatus becomes extremelycumbersome to handle and to be connected to the pipe when the pipediameter is greater than the afore- 3,461,750 Patented Aug. 19, 1969"ice said relatively small maximum value. Also, conventional apparatuspermits the dull bit to be disposed only at a right angle to the pipeduring drilling.

The present invention provides a means by which holes can be quickly andeasily drilled in sewer pipes of substantially any diameter. Evenflat-surfaced tile, concrete or metal structures can be drilled with theinvention. Moreover, the invention provides for the drilling of sewerpipes at an angle so that angled branch lines can be coupled thereto. Tothis end, the invention employs a base which can be readily secured tothe pipe or workpiece either by flexible connecting members extendingabout the pipe or by a vacuum device drawn to and held on the workpieceby suction. A column is pivotally mounted on the base for movement intoany one of the number of operative positions. Generally, the column willbe held either in a position perpendicular to the pipe or in a positioninclined 45 to the pipe. However, the column can be held in otherangular positions as well. The column carries a rotatable shaft to whicha drill bit is coupled and the drive means or the power source for theshaft is shiftably mounted on the column for movement with the shaft andthe drill bit as a unit.

The drilling apparatus of the invention is relatively lightweight sothat it can be moved from place to place with a minimum of effort. Itallows for quick interchange between the flexible connecting memberswhich surround the pipe and the vacuum device which adheres to the outersurface of the pipe. When the vacuum device is not to be used, it can beretracted into a recess in the base and carried as a part of the baseitself.

Provision is also made for improving the cooling of the drill bit andthe flushing of the cut formed in the pipe as it is drilled. To thisend, the shaft for rotating the drill bit has an improved outlet orificefor a coolant which effectively Wets the entire inner surface of thedrill bit regardless of the angle it makes with the pipe to be drilled.Also, the drill bit itself has small holes adjacent to its cutting endthrough which the coolant may pass so that the cut on both sides of thedrill bit will be lubricated and thereby flushed.

It is, therefore, the primary object of this invention to provide animproved drilling apparatus for forming holes in cementitious, metallicor other rigid or relatively rigid structures wherein the apparatus isconstructed so that it can be easily and quickly set into a drillingposition on a pipe of substantially any diameter, as well as aflatsurfaced block.

Another object of this invention is to provide drilling apparatus of thetype described which can be attached to a tile or concrete pipe eitherby flexible connecting members extending about the pipe or by a vacuumdevice drawn to the outer surface of the pipe by suction, whichevermeansis the more convenient for use with a particular workpiece, so thatthe apparatus is not limited to any specific workpiece size or to aspecific range of pipe diameters and it can be used in drilling pipedisposed below the surface of the ground or in proximity to adjacentstructure without disturbing the adjacent soil mass or damaging orotherwise disturbing the adjacent structure.

A further important object of this invention is to provide drillingapparatus of the aforesaid character wherein a pivotally mounted columnmovable into any one of a number of operative positions with respect toa workpiece shiftably mounts the drill bit so that holes can be drilledin tile or concrete pipe at an angle to accommodate angled branch linesfor minimizing initial construction costs of the lines.

Other objects of this invention will become apparent as the followingspecification progresses, reference being had to the accompanyingdrawings.

In the drawings:

FIGURE 1 is a side elevational view of the drilling apparatus in aposition to drill a tile or concrete pipe at an angle, a secondoperative position of the apparatus being shown in dashed lines;

FIGURE 2 is a cross-sectional view taken along line 22 of FIGURE 1;

FIGURE 3 is a cross-sectional view taken along line 33 of FIGURE 1;

FIGURE 4 is a view similar to FIGURE 3 but illustrating the use of thevacuum device instead of the flexible connecting members of FIGURES 1and 3;

FIGURE 5 is a fragmentary, side elevational view of the apparatusillustrating the way in which the vacuum device is coupled to the baseof the apparatus; and

FIGURE 6 is a cross sectional taken along line 66 of FIGURE 5.

Drilling apparatus 10 includes a base 12, a column 14 pivotally mountedon base 12, a carriage 16 shiftably mounted on column 14 for movementlongitudinally thereof, a drive shaft 18 journalled on carriage 16 forrotating cylindrical drill bit 20, and drive means 22 coupled with shaft'18 for rotating the same relative to the carriage. FIGS. 1-3 show howbase 12 is coupled by a pair of flexible coupling members to aworkpiece; whereas, FIGS. 46 show how the base is coupled by a vacuumdevice to a workpiece. The workpiece illustrated in the drawings is apipe 24 formed of tile or concrete and having a predetermined wallthickness through which a hole is to be formed. As will hereinafter bemade clear, the invention is not limited to the drilling of pipe of thistype, but can be used for drlling into metal pipes as well as metal andcementitious blocks, as well as other rigid or relatively rigidstructures.

Base 12 has a rectangular frame-like configuration and includes a pairof generally parallel, transversely L-shaped sides 26 and 28 which areinterconnected by bar-like ends 30 and 32 (FIG. 3). Each of the sides 26and 28 has a pair of mutually perpendicular flanges 34 and 36, eachflange 34 having a pair of spaced levelling screws 38 disposed forengaging pipe 24.

Flange 36 of side 26 has a pair of spaced, open end slots 40 forreceiving links 42 of respective link chains 44 which serve toreleasably couple base 12 to pipe 24. The width of slots 40 is greaterthan the thickness of each link 42 so that the links can be easilyreceived in the slots. However, the width of the links is greater thanthe slot width so that the next adjacent link of each chain will abutthe inner surface of flange 36 and thereby prevent outward movement ofthe chain with respect to the slots. The chain is thereby releasablyheld or coupled to base 12.

Flange 34 of side 28 has a pair of open end slots 46 (FIGS. 3 and 4) forreceiving take-up devices 48 on the corresponding ends of chains 44.Each device 48 includes an internally threaded sleeve 50 and anexternally threaded shaft 52 movable within the sleeve. Each slot 46 hasan enlarged inner extremity which is surrounded by conical surface 54formed by countersinking the area surrounding the enlarged portion ofthe slot. Each sleeve 50 has an end substantially complemental to andnormally bearing against the corresponding surface 54 so that therotation of the sleeve to take up slack in the corresponding chain isfacilitated.

Column 14 has a box-like, tubular construction and is provided with apair of laterally extending arms 56 which are tapped at their outer endsfor threadably receiving screws 58 passing through respective, alignedholes 60 in flanges 36. For purposes if illustration, column 14 isadapted to be mounted in two different positions on base 12. As shown inFIGS. 1, 3, 4, and 5, column 14 is mounted in proximity to end 30. Inthis position, the drill bit will be outboard of end 30 and therebyexternally of base 12 as shown in FIG. 1. To assist in guiding thecolumn into this position, a pair of guide members 62 are secured to theinner surfaces of respective flanges 36 and have V- 4 shaped guidesurfaces 64 (FIGS. 1, 3 and 4) which define shoulders for supporting theouter ends of respective arms 56. When the arms are supported by guidemembers 62, the tapped openings in the arms will be aligned with theholes in flanges 36 to facilitate the coupling of screws 58 to the arms.

Another position for column 14 is inboard of the position shown in thedrawings. To this end, guide members 66, identical to guide members 62,are secured to flanges 36 adjacent to respective holes 60 for supportingarms 56 as screws 58 are threaded into the arms. In the more centralposition, column 14 is disposed to mount drill bit 20 inboard of side 30to enhance the stability of the unit. For this position, column 14 willbe perpendicular to the plane of base 12. For the first mentionedposition of the column, the latter can be perpendicular or inclinedrelative to the plane of the base. When it is perpendicular in the firstposition, the drill bit is capable of drilling near the bell end of pipe24.

. The outer end of column 14 has a pair of cars 68 connected by a pin 70to a rod 72 telescoped within and extending outwardly from one end of atubular member 74. The opposite end of member 74 is connected by a pin76 to a pair of ears 78 rigid to end 32 of base 12 (FIG. 3). Screws 58and pins 70 and 76 provide pivotal mountings so that column 14 can bepivoted into any one of a number of operative positions with respect tobase 12. To hold the column in a fixed position, rod 72 is provided witha number of holes along its length for receiving a pin 80 which isremovably carried at the outer end of tubular member 74. Generally,column 14 will either be inclined at a 45 angle with respect to base 12as shown in full lines in FIG. 1 or at right angles to the base as shownin dashed lines in FIG. 1. However, it can be at any angle provideddrill bit 20 is capable of drilling a hole in the workpiece.

Carriage 16 includes an elongated, transversely C- shaped guide 82 whichis complemental to and slidably disposed on column 14 as shown in FIG.2. A pair of rigid straps 84 (FIG. 1) releasably interconnect guide 82to the column and allow it to shift longitudinally of the column.

To shift carriage 16, a screw 86 is provided, screw 86 being rotatablymounted on a laterally extending projection 88 at the outer end ofcolumn 14 (FIGS. 1 and 2). The screw is also threadably coupled to asleeve (not shown) rigid to guide 82 so that when the screw is rotated,the guide is advanced along column 14. A handle 90, on the outer end ofscrew 86 allows the same to be rotated in opposed directions, wherebyguide 82 may be reciprocated with respect to the column.

A pair of spaced bearing mounts 92 are secured to and extend laterallyfrom guide 82 in a direction away from base 12 when column 14 isinclined. Mounts 92 have bearings 93 for rotatably mounting shaft 18 oncarriage 16 in substantial parallelism to column 14. A sprocket 94 isrigidly coupled to shaft 18 and is connected by a chain 96 to a sprocket98 on the drive shaft 100 of a power source 102 forming drive means 22.Power source 102 is connected by a bracket 104 to guide 82 so that itreciprocates with carriage 16. It can be of any construction, such as anelectric motor, a hydraulic motor, a gasoline motor, or an air motor. Anair motor is preferred over an electric motor for reasons of safetybecause apparatus 10 will oftentimes be used in damp or wet areas belowground level. Also, if the motor is air driven, it can serve theadditional purpose of actuating the vacuum coupling device hereinafterdescribed.

Shaft 18 is threaded at one end and is axially connected to drill bit 20in any suitable manner, such as by a pair of coupling elements 106 onopposed sides of the end wall 108 of the drill bit. Shaft 18 is tubularso that a coolant can be directed into drill bit 20. A conduit 109 iscoupled to the outer end of shaft 18 and is adapted to be connected to asource of coolant, such as water. The

inner end of shaft 18 threadably receives a tip 110 having a T-shapedpassage 112 defining a pair of opposed outlet ports communicating withthe interior of shaft 18. By means of this construction, the coolantissues laterally of the longitudinal axis of the shaft and moreeffectively wets the interior of drill bit 20 than if the coolant wereto issue axially of the shaft. With this construction, more surface areaof the interior of the drill bit is covered by the coolant and the drillbit is thereby more effectively cooled than an axial flow of coolantfrom the shaft.

To enhance the lubrication of the cut made by drill bit 20, the latteris provided with a number of spaced, relatively small holes 114therethrough adjacent to its cutting end. These holes allow the coolantto pass through the drill bit and thereby lubricate both sides of thecut.

Chains 44 are one means of securing base 12 to a workpiece and mayconveniently be used when the pipe diameter is not too large. Generally,the chains will be used for pipe diameters in the range of 6" to 12" andwhere digging around the pipe can be done without much difficulty.Beyond this upper limit, it may be more practical to use vacuumattachment 116 (FIGS. 4-6) to eliminate the digging step. Attachment 116is drawn by suction to the outer surface of the pipe and means isprovided to connect the base to the attachment, whereby the base isrigidly held to the pipe for the drilling operation. This attachment canalso be used for pipe in the small diameter range if the construction ofthe attachment is such as to allow for this.

Attachment 116 includes a plate 118 having continuous inner and outerflanges 120 and 122 (FIG. 6) on one face for defining a continuousrecess 124. A continuous, resilient band or pad 126 is disposed withinrecess 124 and is engageable with the outer surface of pipe 24. The endportions of flanges 120 and 122 have arcuate edges 128 which areslightly concave to follow somewhat the outer contour of pipes in acertain diameter range. To facilitate the forming of these edges, theplate 118 itself is slightly arcuate. The inner flange 120 and thecentral portion of 118 defines a vacuum chamber 130 when pad 126 engagespipe 124. A vacuum device 132 mounted on the outer face of plate 118communicates with chamber 130 for evacuating the same. Device 132 ispreferably a venturi unit which is coupled by a conduit 134 to a sourceof air under pressure. Conduit 134 is coupled with the pressure sourcewhich actuates motor 102 if the latter is of the air-driven type. Avacuum gauge 136 is carried by plate 118 and communicates also withchamber 130 for registering the suction pressure in the chamber.

Plate 118 is releasably coupled to base 12 by means of a pair of tubularcrosspieces 138 which span the distance between flanges 36 of sides 26and 28 as shown in FIG. 6. The ends of crosspieces 138 have notches 140for complementally receiving the upper edges of the flanges 36 tothereby hold the crosspieces in place on the base.

Crosspieces 138 are coupled with plate 118 by a pair of threaded stubshafts 142 which are threadably coupled to bosses 144 integral with theouter surface of plate 118 (FIG. 5). The shafts 142 extend outwardlyfrom plate 118, through respective crosspieces 138 and pro ect outwardlytherefrom. A nut 146 is threadably coupled to the outer end of eachshaft 142 and is disposed to draw plate 118 and crosspieces 138together.

Each flange 36 has a pair of pin-like stops 148 which extend into thecentral opening 150 defined by the sides and ends of base 12. Stops 148are adjacent to the outer edges of flanges 36 and are used to hold plate118 in a retracted position recessed within central opening 150. FIG. 6illustrates the approximate position of plate 118 when it is retracted.To retract the plate, nut 146 is tightened to draw the plate againststops 148 whereupon attachment 116 becomes rigid with base 12. Theapparatus can then be used with chains 44 or can be carried from placeto place with attachment 116 rigidly held thereon.

6 OPERATION When a hole is to be drilled into small diameter pipe in theground, the pipe is exposed and base 12 is placed on it in line with thearea to be drilled. The soil beneath the pipe is also dug away to permitthe chains to extend about the pipe.

With take-up devices 48 in place, the chains are positioned about thepipe and pulled to take up the slack. Then a link of each chain isplaced in. the corresponding slot while the chain remains as taut aspossible. Then the take-up devices are actuated to tighten the chainsand thereby rigidly secure the base to the pipe.

Drill bit 20 can be secured to shaft 18 either before or after the baseis put into place. If an angled hole is to be drilled, column 14 ispositioned in prixitnity to side 30 as shown in FIG. 1 and at the properangle relative to base 12 by adjusting the relative positions of rod 72and tubular member 74. Motor 102 is then coupled to a power source andconduit 109 is coupled to a source of water for cooling. The Water flowis started before the drilling is initiated.

If the bell end of pipe 24 is to be drilled, column 14 will be movedinto the dashed line position of FIG. 1. Where maximum stability of thedrill bit is desired, column 14 is initially positioned in the morecentral position where drill bit 20 extends through central opening 150of base 12. When used in this manner, attachment 116 is removed from thebase.

With shaft 18 rotating and water flowing into drill bit 20, screw 86 isrotated by the manual rotation of handle to advance carriage 16progressively along column 14. Drill bit 20, thus, moves into drillingengagement with pipe 24 and progressively drills the same. The rate atwhich the carriage is advanced will depend upon the rotational speed ofshaft 18 and the type of material forming pipe 24.

During the drilling operation, water is directed laterally from tip 110and wets substantially the entire inner surface of drill bit 20 to coolthe same. The Water, also, flows to the drilling area and into one sideof the cut as well as through holes 114 and to the opposite side of thecut. In this way, the cut is more effectively flushed to enhance thedrilling step itself.

After the drilling has been completed, the portion removed from the pipecan be readily removed from the drill bit after the latter has beenmoved away from the pipe and its rotational movement stopped. The drillbit is moved away from the pipe by rotating screw 86 in the oppositedirection.

If the pipe diameter is above the range at which it is practical to usechains 44, the chains are not used and attachment 116 is employed. Toutilize the attachment, it is first loosely coupled to the base so thatthere can be relative movement between these components. Plate 118 isthen forced toward the pipe to cause pad 126 to compress as it engagesthe pipe. Then, vacuum device 132 is actuated to evacuate chamber 130.This holds plate 118 by suction to the pipe, whereupon nuts 146 can betightened to force base 12 toward the pipe and into a fixed positionwith respect to attachment 116. The drilling step can then be performedwith column 14 either perpendicular to or at an angle to the pipe. Thewater flow is provided in the usual manner to cool the drill bit and toflush the cut.

Leveling screws 38 are generally used when attachment 116 is used. Theyare generally not needed for the smaller diameter pipe since each of theends 30 and 32 has an arcuate edge proximal to the pipe which provides apair of contact points which are transversely spaced relative to thelongitudinal axis of the pipe. Within a certain range of pipe diameters,these contact points serve to align the base longitudinally of the pipewhen the base is first put into place. Above this range, the contactpoints become less effective and, generally, the

leveling screws should then be substituted for this alignment feature.The leveling screws themselves then become point contacts engaging thepipe.

The leveling screws also serve to support apparatus 10 when the latteris not in use. In this respect, the screws protect pad 126 from damagewhen attachment 116 is retracted into base 12.

Apparatus 10 is also suitable for use in drilling flat surfaces. To thisend, the workpiece-engaging pad of plate 118 will have a working facethat is planar rather than one that is arcuate as shown in FIG. 6. Thus,the invention is not limited to the drilling of pipe.

Apparatus It) provides a driling unit having a simple and ruggedconstruction and one which is highly portable and can be quickly andeasily set up for use either on tile or concrete pipe or a flat-surfacedcementitious structure.

While one embodiment of this invention has been shown and described, itwill be apparent that other adaptations and modifications can be madewithout departing from the true spirit and scope of the invention.

What is claimed is:

1. Drilling apparatus comprising: a base frame having a pair of opposedsides and a pair of opposed ends defining a central opening, each ofsaid sides being transversely L-shaped to present a pair ofinterconnected flanges, one flange of one of the sides having a pair ofspaced, open end slots therein, one flange of the other of said sideshaving a pair of spaced, open end slots therein aligned with respectiveslots of said one side; a pair of link chains adapted to extend aboutsaid workpiece to couple the base frame thereto when the perimeter ofthe workpiece is less than a predetermined value, each chain having atake-up device at one of its ends, the takeup device is adapted toextend through the slots of said one side and toengage said one side tothereby releasably couple the corresponding ends of the chains to thebase frame, the slots of the other side having a width less than thewidth of the links of corresponding chains but greater than thethickness of said links to thereby permit the links of said chains to beselectively placed into the lastmentioned slots to couple the oppositeends of the chain to the base frame, whereby the latter may be secured tthe workpiece when the take-up devices are actuated to tighten saidchains; a vacuum plate having a resilient, workpiece-engaging,continuous band defining a vacuum chamber when the band engages saidworkpiece; a vacuum device carried by said plate and adapted to beconnected to a vacuum source for evacuating aid chamber; means carriedby said plate for shiftably mounting the latter on said base frame withthe plate being aligned with said central opening thereon, said mountingmeans including structure for urging said base frame toward said platewhen the latter is held to said workpiece by suction, whereby the baseframe may be moved into a fixed position relative to said plate whensaid chains are not used, each of said sides having a stop extendinginto said central opening, said structure being disposed to move saidvacuum plate into a retracted location Within said central opening andagainst said stops When said chains are to be used to couple said baseframe to said workpiece; a column having a carriage mounted thereon forlongitudinal movement with respect thereto; means pivotally mounting oneend of said column on said sides adjacent to one end of the base framefor movement in a plane substantially perpendicular to the plane of saidbase frame, said column being movable into any One of a number ofoperative positons with respect to the plane of said base frame; meanscarried by said base frame and coupled with said column for releasablyholding the same in an operative position; a tubular shaft journalled onsaid carriage in substantial parallelism with said column; drive meansmounted on' said carriage for rotating said shaft; a cylindrical drillbit; means releasably and axially mounting one end of the drill bit onsaid shaft with one end of the shaft extending into the drill bit, thelatter having a number of holes therethrough adjacent to the outer endthereof; a tubular coupling secured to said one end of the shaft andhaving a T-shaped fluid passage therethrough, said passage communicatingwith the interior of said shaft to cause a coolant entering said shaftat a location adjacent to its opposite end to issue from said couplingin opposed directions and laterally of the longitudinal axis of theshaft; and a screw carried by said column and coupled with said carriagefor reciprocating the latter with respect to said column.

2. Drilling apparatus as set forth in claim 1, wherein said drive meansincludes an air motor adapted to be coupled to a source of air underpressure, said vacuum device having a venturi section coupled with saidair motor to produce a vacuum in said chamber when said band engagessaid workpiece.

3. Drilling apparatus as set forth in claim .1, wherein said holdingmeans for said column includes an extensible, adjustable brace securedto the opposite end of the column and to said base frame adjacent to theopposite end thereof.

4. Drilling apparatus as set forth in claim 1, wherein said ends of thebase frame have means defining spaced contact points for engaging theworkpiece and aligning the base frame with respect thereto when theworkpiece has a convex outer surface, each of said sides of said baseframe having a pair of spaced leveling screws for engaging the workpiecewhen said defining means become ineffective for aligning said baseframe.

5. Drilling apparatus comprising: a base having a central opening and apair of spaced sides and adapted to be disposed adjacent to a workpieceto be drilled; a vacuum device disposed in said opening and disposed forfixedly engaging said workpiece to secure the base to the outer surface,said vacuum device having a pair of spaced crosspieces shiftably mountedthereon, said crosspieces being disposed to engage the opposite sides ofsaid base in bridging relationship thereto; means for forcing saidcrosspieces and thereby said base toward said vacuum device when thelatter fixedly engages said workpiece and when said crosspieces engagethe sides of said base, whereby the base is held in a fixed locationrelative to said vacuum device; a column pivotally mounted on said basefor movement in a plane extending transversely of said outer surfacewhen the base is secured thereto; means coupled with said column andcarried by said base for releasably holding said column in any one of anumber of operative positions with respect to said surface; a carriageshiftably mounted on said column for movement longitudinally thereof; adrill bit rotatably mounted on said carriage and disposed for drillingsaid surface when said column is in an operative position and as saidcarriage moves toward said workpiece; drive means on said carriage forrotating said drill bit; and means mounted on said column and coupledwith said carriage for controllably moving the latter along said column,whereby said drill bit may be progressively moved toward and intodrilling engagement with said surface.

6. Drilling apparatus as set forth in claim 5, wherein each side of saidbase is provided with a stop extending into said opening, said forcingmeans including a screw disposed for shifting said vacuum device into aretracted position in engagement with said stops.

7. Drilling apparatus as set forth in claim 5, wherein the ends of eachof said crosspieces are notched to receive the corresponding sides ofsaid base and thereby to releasably maintain said crosspieces inbridging relationship to said sides.

8. Drilling apparatus comprising: a base adapted to be disposed adjacentto a workpiece to be drilled, said base being provided with a pair ofarcuate end edges for engaging said workpiece when said outer surfacethereof is convex; a number of leveling screws shiftably carried by saidbase and disposed for engaging the outer surface of said workpiece whenthe curvature of said outer surface is less than the curvature of saidend edges; means coupled with said base for releasably securing thelatter to the outer surface of said workpiece; a column pivotallymounted on said base for movement in a plane extending transversely ofsaid outer surface when the base is secured thereto; means coupled withsaid column and carried by said base for releasably holding said columnin any one of a number of operative positions with respect to saidsurface; a carriage shiftably mounted on said column for movementlongitudinally thereof; a drill bit rotatably mounted on said carriageand disposed for drilling said surface when said column is in anoperative position and as said carriage moves toward said workpiece;drive means on said carriage for rotating said drill bit; and meansmounted on said column and coupled with said carriage for controllablymoving the latter along said column, whereby said drill bit may beprogressively moved toward and into drilling engagement with saidsurface.

9. Drilling apparatus comprising: a base adapted to be disposed adjacentto a workpiece to be drilled; means coupled with said base forreleasably securing the latter to the outer surface of said workpiece; acolumn pivotally mounted on said base for movement in a plane extendingtransversely of said outer surface when the base is secured thereto;means coupled with said column and carried by said base for releasablyholding said column in any one of a number of operative positions withrespect to said surface; a carriage shiftably mounted on said column formovement longitudinally thereof; a tubular shaft journalled on saidcarriage; a drill bit for drilling said surface when said column is inan operative position and as said carriage moves toward said workpiece,said drill bit including a tubular member secured to and partiallytelescoped on said shaft, the inner end of the shaft having a laterallyextending fluid outlet, whereby a coolant directed through said shaftWill issue from said inner end thereof in a direction transverse to itslongitudinal axis; drive means on said carriage for rotating said drillbit; and means mounted on said column and coupled 'with said carriagefor controllably moving the latter along said column, whereby said drillbit may be progressively moved toward and into drilling engagement withsaid surface.

10. Drilling apparatus comprising: a base having a pair of spaced,opposed sides and a pair of spaced, opposed ends defining a centralopening, said base adapted to be disposed adjacent to a workpiece to bedrilled; means coupled with said base for releasably securing the latterto the outer surface of said workpiece; a column; a carriage shiftablymounted on said column for movement longitudinally thereof; a drill bitrotatably mounted on said carriage and disposed for drilling saidsurface when the column is in an operative position with respect theretoand as said carriage moves toward said workpiece; first means on saidsides of the base for mounting said column for pivotal movement in aplane extending transversely of said outer surface and for positioningsaid drill bit exteriorly of and adjacent to one of the ends of thebase; second means for mounting said column at a location with saiddrill bit movable through said central opening; means coupled with saidcolumn and carried by said base for releasably holding said column in anoperative position with respect to said surface; drive means on saidcarriage for rotating said drill bit; and means mounted on said columnand coupled with said carriage for controllably moving the latter alongsaid column, whereby said drill bit may be progressively moved towardand into drilling engagement with said surface.

References Cited UNITED STATES PATENTS 3,169,415 2/1965 Welty 77-42 XR2,977,827 4/1961 Wenz 77-68 XR 2,887,910 5/1959 Williamson 7759.12,222,910 11/ 1940 Lucker 77--14 XR FOREIGN PATENTS 451,950 8/1936 GreatBritain. 583,158 12/1946 Great Britain.

FRANCIS S. HUSAR, Primary Examiner US. Cl. X.R.

